The Clinical and Molecular Epidemiology Shared Resource (CMESR) was established in 2000 as a repository of human biologic specimens and linked epidemiologic data for cancer biomarker studies, and it became a full shared resource in 2002. The CMESR is a source of biologic samples (blood components, buccal cells, and extracted DNA) linked to clinical and epidemiologic data from subjects with and without cancer. Breast, lung, prostate, head and neck, and colorectal cancers are included at the present time. With such a resource, the Lombardi Comprehensive Cancer Center (Lombardi) can fulfill its mission to conduct population studies of cancer risk factors and prevention. By accruing subjects and collecting their biologic samples at Lombardi and the Washington Hospital Center (MedStar Health, a sister institution in Washington, DC), the CMESR has grown to become a comprehensive resource for the Lombardi scientific community, both in terms of supplying linked data and specimens to investigators, and conducting pilot studies to accrue such materials (e.g., as preliminary data in support of grant applications). Personnel from the CMESR approach cancer and non-cancer subjects in the clinic and obtain consent to collect specimens and administer questionnaires, and the subjects agree to allow these materials to be shared with investigators. Researchers from different Lombardi programs have used these materials to develop biomarkers of early detection, progression, recurrence and prognosis, for studies of cancer risk, and for studies assessing the utillzation of screening and counseling resources by cancer patients. This resource offers additional services for its users, including customized data reports on clinical and epidemiologic characteristics of the study subjects, with information on outcomes and follow-up; and high-quality data entry for questionnaires, food frequency surveys, and other research forms. Twenty-two projects in three Lombardi programs were supported by the CMESR in 2008. Dr. Christopher Loffredo, the Director of the resource, is a cancer epidemiologist with a laboratory-based background in toxicology. The CMESR has two Associate Directors with complementary expertise: Dr. Celia Byrne, an epidemiologist with expertise in study design and evaluation, and Dr. Yun-Ling Zheng, a molecular epidemiologist with expertise in cancer genetics and a wide array of laboratory techniques.